Hydraulic pop riveters



June 7, 1966 f R. M` ELLloTT ETAL 3,254,522

HYDRAULIC POP RIVETERS Filed Jan. 29, 1964 4 Sheets-Sheet 1 l. W 66 62'i1/f my 66 74 100 76W R. M. ELLIOTT ETAL 3,254,522

HYDRAULIC POP RIVETERS June 7, 1966 4 Sheets-Sheet 2 Filed Jan. 29, 1964June 7, 1966 R. M. ELLloTT ETAL 3,254,522

HYDRAULIC POP RIVETERS Filed Jan. 29, 1964 4 Sheets-Sheet 3 June 7, 1966R. M. ELLloTT ETAL 3,254,522

HYDRAULIC POP RIVETERS Filed Jan. 29, 1964 4 Sheets-Sheet L i l l529 Mkx) \/S United States Patent O HYDRAULIC POP RIVETERS Richard M.Elliott, Beverly, Mass., and Richard B. Maxner, Amherst, N.H., assignorsto United Shoe Machinery Corporation, Flemington, NJ., a corporation ofNew Jersey Filed Jan. 29, 1964, Ser. No. 340,975

` 3 Claims. (Cl. 72-391) This -invention relates to power tools, andmore particularly to a fluid-actuated pull gun for the setting of blindrivets :and the like.

In the manufacture of many articles it is desirable to connect two ormore work sheets or work pieces together by means of rivets undercircumstances in which it is impossible or inconvenient to obtain accessto opposite ends of the rivets for the performance of ordinary rivetupsetting operations. To accomplish the desired result, it lhas grown tobe the practice to employ blind rivets of the type in which a rivet bodyis provided with a longitudinal bore which receives a mandrel having anenlarged head disposed adjacent the remote end of the rivet body. Themandrel extends through the rivet and projects beyond the rivet body tobe gripped by a pull-ing tool. After the rivet has been inserted fromone side of the assembled work pieces, a pulling yforce may be exertedby the pulling tool from that same side, pulling the mandrel head intothe rivet body, upsetting the remote end thereof and securing the rivetin the Work pieces.

In the usual -bl-ind rivet setting operation, a force is exerted uponthe mandrel sutlcient not only t-o pull the man- -drel head through itsupsetting motion, but also to break off the mandrel once the rivet isset. The shock of the sudden release of strain when the mandrel breaksis usually sufficiently severe to cause the tool to jump uncontrollably.In most applications the sudden jump of the tool when the mandrel breakscauses little or no harm to the work pieces. However, it has been foundthat Where extremely thin sheets of material a-re to be subjected to ablind riveting operation, the occurrenceof dimpling must be expectedfrom the rivet setting tools now available. After a rivet settingoperation, an inspection of the thin sheet material generally reveals aseries of small indentations or dimples.

It is accordingly an object of the invention Ito provide `a hand toolfor applying a smooth pulling force to the mandrel and in which there isno substantial shock imp-arted to the tool upon the severance of themandrel.

To this end there is provided a rivet setting tool having a oneway checkvalve arrangement which restricts the ilow of hydraulic fluid in onedirection through the valve during a pulling operation so as to effect asmooth pulling `and breaking operation, butwhich allows the uid toreadily pass in an opposite direction through the valve after completionof a rivet setting operation.

The above and other features of the invention, including novel detailsof construction and combinations of parts, will now be described in thefollowing specification and will be pointed out in the appended claims.It will be understood that the particular dev-ice embodying theinvention is shown by way of illustration only and not as a limitationof -the invention. The principles and features of this invention may beemployed in varied and numerous embodiments without departing from thescope of the invention.

In the drawings,

FIG. l is a vertical sectional view illustrating the details ofconstruction of a blind rivet setting tool constructed in accordancewith the preferred embodiment of our invention;

FIG. 2 is a vertical sectional view similar to FIG. 1

3,254,522 Patented June 7, 1966 ICC but showing the relativedispositions of the movable parts at the end of a rivet pulling stroke;

PIG. 3 is an exploded detail perspective view of the one-way check valvemechanism;

FIG. 4 is a front sectional View of the trigger and air inlet mechanismof the tool; and 4 FIGS. 5-7 show the rivetting processdiagrammatically.

Referring to FIG. l, the preferred embodiment of the -invention includesa pneumatic cylinder 2 for receiving pressurized air from a source notshown. 'Ihe pneumatic cylinder 2 has at one end a recessed bottom 4 andat the other end an enlarged collar portion 6. An air pipe 8 (FIG. 4)communicates with an annular air chamber 10 formed by the recessedbottom 4. Attached to the enlarged collar 6'is an upper housing 12 whichserves as a handle and contains a trigger assembly .14 for actuating thedevice and a hydraulic cylinder 16. Separating lthe pneumatic cylinder 2and the upper housing 12 is a metal diaphragm 18 having an aperture 20.

Oper-atively connecting the hydraulic cylinder 16 and the pneumaticcylinder 2 is a common rod 22. Mounted upon the end of the rod 2.2disposed in the pneumatic cylinder 2 is a piston 24 carrying a seal ring26 and having a hub portion 28 which in its extreme low position restsupon a raised portion 30 of the bottom of the cylinder 2, the raisedportion 30 being dened by the recess 4. Mounted upon the other end ofthe-rod 22 disposed in the hydraulic cylinder 16, are .seal-ing members32.

The metering feature of the invention is located lat the upper end ofthe hydraulic cylinder 16, as viewed in FIGS. 1 and 2 where there isarranged a flanged restrictor housing 34 having a barrel portion 36which is disposed within the hydraulic cylinder 16, a ange portion 38which rests upon a sealing ring 40 on the end of the cylinder 16 and laninterior shoulder 39. The restrictor housing 34 has a. bore 42 which isenlarged at its upper portion, the enlargement dening the shoulder 39.In the enlarged portion there is disposed a restrictor 44 which has anedge width of less than the axial length of the enlarged portion -of thebore 42 so that the restrictor 44 tits loosely, with axial play, in thebore 42. The restrictor 44 is essentially an orice plate having arelatively small central orifice 44a and several relatively'largeperipheral orifices or recesses 44b (FIG. 3). A restrictor seat 46,having a relatively large or'iiice 48,' rests upon the upper face of theflange 38. When the tool is not performing a pulling stroke, therestrictor 44 is supported by the interior shoulder 39 in the enlargedportion of the bore 42 of the restrictor housing 34. The restrictor seat46, the restrictor housing 34 containing the restrictor 44, the sealingring 40, and theextreme upper end of the hydraulic cylinder 16 arefitted into a cylindrical recess 50 in the upper regions of the upperhousing 12.

VFormed integral With the upper housing 12 at its upper extremity is adraw cylinder 52 which houses the rivet pulling apparatus of theinvention. The dra-w cylinder 52 communicates with the hydrauliccylinder 16 through a channel 54 which, together with the restrictorhousing 34, constitute a conduit for the flow of uid between thehydraulic cylinder and the draw cylinder. Threadedly received in theforward end of the cylinder 52 is a nose housing 56 which at its forwardend threadedly receives a nosepiece 58 having an axial bore 59 suitablefor receiving a blind rivet. The nose housing 56 is provided with Wrenchflats 60 for receiving the jaws of a wrench. The rivetpulling mechanismincludes a seal sleeve 62,

disposed in the draw cylinder 52, having a ange portion,

64 fitting into a recess 66 in the inside wall of the cylinder 52. Asleeve retainer ring 68 is located in the recess 66 and is tted betweenthe flange 64 and the nose housing 56. A sleeve O ring '7.0 is receivedin a recess in the outer wall of the seal sleeve 62. An axial bore 72 inthe seal sleeve 62 has an enlarged section 74 toward the front of thetool. In recesses in the bore 72 are received sealing members 76.

A draw rod 78 is axially disposed in the draw cylinder 52, beingslidably retained in the bore 72, and has an axial bore 80 throughoutits length and an enlarged head 82 at its rearward end. The draw rod 78is threadedly connected to a pulling head adapter 84 which'is in turnthreadedly connected to a jaw guide 86 which encircles jaws 88. Thepulling head adapter 84 has an axial bore 90 in alignment with the bore80. A jaw pusher 92 is received in the pulling head adapter 84 and has aflange portion 94 spaced lfrom the forward face of the pulling headadapter 84. The jaw pusher 92 has an axial bore 96 in alignment with thebore 90. A coil spring 98 is inserted in the bore 90 of the pulling headadapter 84 and at its forward end abuts the rearward face of the jawpusher 92 and at its rearward end abuts the forward face of the draw rod78. The bore 74 receives an annular face plate 100 which is disposedaround the draw rod 78. Mounted on the pulling head adapter 84 areretaining rings 102, one recessed in the outer wall of the pulling headadapter 84, and one fitted around the adapter 84 and abutting therecessed retaining ring. Extending from the retaining rings 182 to theface plate 160 is a return spring 104 which is coiled around portions ofthe outer surfaces of the adapter 84 and the draw rod 78, and isdisposed within the bore 74 of seal sleeve 62 and within a portion ofthe nose housing 56. The return spring 104 urges the draw rod 78 towardsthe nose section of the draw cylinder.

Rearward of the flanged seal sleeve 62 there is fixed to the draw rod adraw cylinder piston assembly which includes a collar portion 166 of thedraw rod 78 abutting an annular disc 108 mounted on the draw rod. Asleeve member 110 is disposed upon the draw rod 78 with its forward faceabutting the disc 108. An enlarged portion 112 of the sleeve member 110has a recess 114 in its outer wall which receives sealing members 116which slidably engage the inner wall of the draw cylinder 52.'

Between the disc 108 and the enlarged portion 112 of the sleeve 110 arelocated sealing members 118 which slidably abut the inside wall of thedraw cylinder 52. The enlarged portion 112 of the sleeve member 110receives in its axial bore the head S2 of the draw rod 78. The disc 108,the sealing members 118, and the sleeve member 110 form, in effect, apiston on the operator end of the draw rod, slidable in the drawcylinder 52.

A threaded hole 120 is located on the top of the draw cylinder 52, forthe purpose of admitting fresh hydraulic fluid, and is closed by a screw122. A bead 124 extends around the periphery of the rearward end of thedraw `cylinder 52 for the purpose of receiving a deflector 126 having arecess 128 in its inner wall for receiving the bead. FIGS. l, 2 and 4illustrate the trigger and air inlet mechanism of the invention whichincludes a trigger 130 pivoted about a pivot pin 132 by which thetrigger isl connected to the upper housing 12. A trigger spring 134rests upon the pivot pin 132 and is attached at its ends to a spring pin136 in the upper housing 12 and a connecting pin 138 on the trigger 130.The trigger spring 134 urges the trigger 130 in a forward direction andresists movement of the trigger rearward.

The connecting pin 138 retains one end of a toggle 140 which at itsother end is connected by another connecting pin 142 to one end of atube 144. The tube 144 is slidably received in a sleeve 146 having anenlarged portion 148 which is retained lby the upper housing 12 andwhich has an aperture 150 (FIG. 4) in alignment with the air pipe 8. The`lower end of the sleeve 146 forms the upper portion of a valve chamber152 defined by the upper housing 12. The valve chamber 152 retains avalve plug 154 having a peripheral recess 156 with a sealing ring 158disposed therein. A floating rubber valve disc 160 is disposed in thelower end of the sleeve 146 and the upper portion of the valve chamber152. A channel 162 (FIG. 4) in the upper housing 12 connects the valvechamber 152 to a tube T which is in turn connected to a source ofpressurized air.

Before using the tool, the hydraulic system is completely filled with asuitable hydraulic medium, such as oil and the like, through the hole120, and capped with the screw 122. The tool is connected to a source ofcompressed air so that the air is available in the tube T. The mandrelof a blind rivet is inserted through the bore 59 of the nosepiece 58into the aperture formed by the jaws 88 and into the bore 96 of the jawpusher 92. The body of the rivet is then inserted into aligned aperturesprovided in the work pieces which are to be fastened together.

The trigger 130 is squeezed so as to move the connecting pin 138 in arearward and downward direction. The downward movement of the pin 138causes the toggle 140 to exert a downward force on the tube 144. As isillustrated in FIG. 4 air from the tube T is readily admitted throughthe channel 162 into the valve chamber 152. The air is restricted by thelower portion of the sleeve 146 to entering the valve 'chamber 152 at apoint beneath the valve disc 160 which, when the tool is inoperative,rests upon the valve plug 154. Accordingly, when pressurized air isadmitted to the valve chamber 152 it lifts the valve disc 160 off thevalve plug 154 and pushes it against a downward facing shoulder in thesleeve 146 thereby effecting an air tight seal. However, when the tube144 is pushed downward, its lower end engages the valve disc 160 andforces it downward, breaking the seal and permitting the pressurized airto escape through the aperture 150 int-o the air pipe 8.

Air under pressure is accordingly channeled into the pneumatic cylinder2, to the annular chamber 10` around the raised portion 30 of the bottomof the cylinder 2. Acting against the underface of the piston 24, theair forces the piston 24 upwards. The aperture 20 provides foratmospheric pressure only on the upper surface of the piston 24.l Upwardmovement of the piston 24 effects an upward movement of the rod 22 intothe hydraulic cylinder 16. It will be understood that the references toupward movements and the like are for convenience in referring to thedrawings, and that actually the device is usable in any attitude, forexample upside-down.

As the rod 22 progresses into the hydraulic cylinder 16 the hydraulicuid therein is forced toward the draw cylinder 52. The ,path of thehydraulic uid leaving the hydraulic cylinder 16 is narrowed in the bore42 Where the fluid presses against the restrictor 44 urging it againstthe underside of the restrictor seat 46 (FIG. 2). When the restrictor 44is flush with the underside of the restrictor seat 46, the centralorifice 44a ofthe restrictor (FIG. 3) is in alignment with the orice 48of the restrictor seat, allowing the flow of hydraulic fluidtherethrough. The peripheral recesses 44h of the restrictor are coveredor masked by the underside of the restrictor seat and so do not afford apassage for the ow of fluid. Thus, when the hydraulic medium is beingforced from the hydraulic cylinder 16 into the draw cylinder 52 it mustpass through the single channel defined by the orifice 44a.

Fluid emitting from the channel 54 enters the draw cylinder 52 at apoint forward of the disc 108 mounted on the draw rod 78. The mediumacts on the disc 108 so that the draw rod 78 is displaced in a rearwarddirection. At the same time the pulling head adapter 84 and the jawguide 86 are moved in the same direction, away from the nosepiece 58.The coil spring 98 acting through the jaw pusher 92, tends to push thejaws 88 forward against the conical back surface of the jaw guide 86.The jaws 88 accordingly oppose the rearward movement and there occurs arelative movement between the opposed and adjacent surfaces of the jaws88 and the conical section of the jaw guide ,86. Because of thisrelative movement the jaws 88 are moved toward one another and the rivetis firmly gripped. The jaws are drawn rearwardly by the conical sectionf the jaw guide 86, causing the jaws to be further wedged together andthe rivet mandrel to be still more firmly gripped by the jaws. Themandrel is thereby moved rearwardly until the mandrel tears olf at itsdesigned breaking point.

It is at this point that a recoil is experienced in devices heretoforeavailable. However, because of the restricted llow of hydraulic fluidinto the draw cylinder, with its attendant smoother application ofpressure, the present device operates with negligible recoil, making thedevice suitable for work on extremely thin sheets.

FIGS. -7 illustrate the fastening together of a pair of work pieces S, Sby a blind rivet R. FIG. 5 shows the rivet R in place prior to its beingpulled by the pulling means of the tool. The rivet has been placed inthe nosepiece 58 and has been inserted through alined apertures of thetwo sheets S and S. Referring to FIG. 6, when the jaws 88 of the toolgrip a mandrel M and pull away from the work pieces, an enlarged headportion H of the mandrel M is caused to upset the end of the rivet Rremote from the nosepiece 58 of the gun. FIG. 7 shows the work pieces S,S joinedtogether by the rivet R, the mandrel M having broken away andthe gun having been removed.

After the rivet has been broken the operator releases the trigger 130.The valve disc 160, no longer held down by the tube 144, is again forcedby the -pressurized air int-o a sealing position. Referring to FIG. 4,it may be :seen that when the tube 144 is raised ofI the valve disc 160a channel from the pneumatic cylinder to the atmosphere exists throughthe air pipe 8, the aperture 150, and the tube 144 which is incommunication with the interi-or of the upper housing 12 which is opento atmospheric pressure. As the return spring 104 moves the draw rod 78toward the nosepiece 58, the hydraulic uid is forced back through thechannel 54.

The check valve which metered the ilow of fluid into the draw cylinder52 now acts to expedite the return of the fluid into the hydrauliccylinder 16. T he downward ow of fluid from the draw cylinder forces therestrictor 44 downward until it rests upon the shoulder 39 in therestrictor housing 34. The shoulder permits substantial alignment of theperipheral recesses 44b of the restrictor 44 with the bore 42. Theorifice 48 is still aligned with the orifice 44a. Accordingly, wheniiowing into the hydraulic cylinder the -iluid passes through theorifice 44a of the restrictor 44 and also through the peripheralrecesses 44b. Thus, the restrictor 44 represents one small channel forHow in the working stroke and several large channels for ilow in thereturn stoke, facilitating a smooth working stroke and a rapid returnstroke.

The entrance of hydraulic uid into the upper end of the hydrauliccylinder 16 forces the rod 22 into the pneumatic cylinder until thepneumatic piston 24 again rests upon the raised portion of the pneumaticcylinder bottom 30. The tool is then ready for another operation. Thebroken shank generally falls from the nosepiece 58; however, on someoccasions it has been known to eject out the back of the draw rod. Toprotect the operator from such a possibility the deflector 126 sprovided on theA operator end of the draw cylinder 52. The deector 126is readily removable and replaceable.

Having thus disclosed our invention and described in detail a preferredembodiment thereof, we claim as new and desire to secure by LettersPatent of the United States:

1. In a rivet setting tool for the pulling of blind rivets and the likewhich contain a mandrel member to be broken at the completion of therivet setting operation, said tool having a fluid supply cylinder andpiston assembly, a draw cylinder connected t-o the uid supply cylinder,a draw rod slidably disposed in the draw cylinder having rivet grippingmeans on one end and a piston on the other end, a conduit extending fromthe iiuid supply cylinder to the draw cylinder, and means for forcingliuid from the supply cylinder to the draw cylinder to initiate aWorking stroke of said tool, that improvement comprising means forpreventing recoil action of said tool, said last means includingmetering means disposed in said conduit and responsive to the flow ofthe lluid from the fluid cylinder to the draw cylinder to restrict saidflow during said working stroke, whereby said restricted ow of uidprevents recoil action by retarding excessive travel of said piston whenthe mandrel of the rivet is broken.

2. In a rivet setting tool for the pulling of blind rivets and the likewhich contain a mandrel member to be broken at the completion of therivet setting operation, said tool 4 having a fluid supply cylinder andpiston assembly, a draw cylinder connected to the fluid supply cylinder,a draw rod slidably disposed in the draw cylinder having rivet grippingmeans on one end and a piston on the other end, a conduit extending fromthe uid supply cylinder to the draw cylinder, and means for forcingfluid from the supply cylinder to the draw cylinder to initiate aworking stroke of said tool, that improvement comprising means forpreventing recoil action of said tool, said last means includingmetering means disposed in said conduit and responsive to the ow of theiluid from the iiuid cylinder to the draw cylinder to restrict said flowduring said Working stroke, whereby said restricted ow of fluid preventsrecoil action by retarding excessive travel yof said piston when themandrel of the rivet is broken, and said metering means being responsiveto a reversal in the direction of said ilow to assume a substantiallynon-restricting attitude in said conduit.

3. In a rivet setting tool for the pulling of blind rivets and the likewhich contain a mandrel member to be broken at the completion of therivet setting operation, said tool having a iuid supply cylinder andpiston assembly, a draw cylinder connected to the fluid supply cylinder,a draw rod slidably disposed in the draw cylinder having rivet grippingmeans on one end and a piston on the other end, and a conduit extendingfrom the iluid supply cylinder to the draw cylinder, that improvementcomprising means for forcing fluid from said supply cylinder to saiddraw cylinder to initiate a working stroke of said tool, said meanslbeing operable to cause ow from said draw cylinder to said fluid supplycylinder, means for preventing recoil action of said tool, said lastmeans including metering means disposed in said conduit and responsiveto the flow of the iluid from the iiuid supply cylinder to the drawcylinder to restrict said flow during said working stroke, lwhereby saidrestricted flow of fluid prevents recoil action by retarding excessivetravel of said piston. when the mandrel of the rivet is broken, and saidmetering means being responsive to flow of the uid from the drawcylinder to the fluid supply cylinder to assume a substantiallynon-restricting attitude in said conduit.

References Cited by the Examiner UNITED STATES PATENTS 2,526,956 10/1950Kugler 218-48 2,820,566 1/1958 Van Hecke 218-47 3,082,898 3/1963 Bosch218-47 3,088,618 5/1963 Pickford 218-48 3,110,924 ll/l963 Wartian 16-523,138,177 6/ 1964 Cutler 138-46 CHARLES W. LANHAM, Primary Examiner.

GRANVILLE Y. CUSTER, JR., Examiner.

G. P. CROSBY, Assistant Examiner.

1. IN A RIVET SETTING TOOL FOR THE PULLING OF BLIND RIVETS AND THE LIKEWHICH CONTAIN A MANDREL MEMBER TO BE BROKEN AT THE COMPLETION OF THERIVET SETTING OPERATION, SAID TOOL HAVING A FLUID SUPPLY CYLINDER ANDPISTON ASSEMBLY, A DRAW CYLINDER CONNECTED TO THE FLUID SUPPLY CYLINDER,A DRAW ROD SLIDABLY DISPOSED IN THE DRAW CYLINDER HAVING RIVET GRIPPINGMEANS ON ONE END AND A PISTON ON THE OTHER END, A CONDUIT EXTENDING FROMTHE FLUID SUPPLY CYLINDER TO THE DRAW CYLINDER, AND MEANS FOR FORCINGFLUID FROM THE SUPPLY CYLINDER TO THE DRAW CYLINDER TO INITIATE AWORKING STROKE OF SAID TOOL, THAT IMPROVEMENT COMPRISING MEANS FORPREVENTING RECOIL ACTION OF SAID TOOL, SAID LAST MEANS INCLUDINGMETERING MEANS DISPOSED IN SAID CONDUIT AND RESPONSIVE TO THE FLOW OFTHE FLUID FROM THE FLUID CYLINDER TO THE DRAW CYLINDER TO RESTRICT SAIDFLOW DURING SAID WORKING STROKE, WHEREBY SAID RESTRICTED FLOW OF FLUIDPREVENTS RECOIL ACTION BY RETARDING EXCESSIVE TRAVEL OF SAID PISTON WHENTHE MANDREL OF THE RIVET IS BROKEN.